Electric-heated furnaces, such as those commonly used for annealing, generally heat the central furnace cavity by employing electric resistance heating elements in the form of long ribbons arranged in a serpentine pattern. The furnace will normally have an outer metal casing and, immediately interior of that casing, an insulated region. In earlier days, it was the practice to form this insulating region from firebrick or other such refractories and to then secure heater hanger supports between adjacent courses of firebrick.
More recently, electric furnaces have used ceramic fiber materials for wall insulation, and in some instances have extended support hooks completely through this insulation and attached them to the outer casing. Still more recently, such a direct heat path to the outer casing has been avoided when using ceramic fiber by the use of a construction such as that shown in U.S. Pat. No. 4,088,825, issued May 9, 1978. In this construction, anchors of matallic or ceramic construction are provided as such electric heater hangers for use with an insulating wall formed from a plurality of layers of ceramic fiber batts which are compressibly stacked, one atop another, contiguous to the outer casing. The anchors include supporting hooks and are located between pairs of adjacent ceramic fiber batts so that the hooks project the desired distance inwardly from the interior face of the insulation to support the electric heating element ribbons. Although such a construction provides improvement in reducing the time which it takes workers to re-line an electric furnace, compared to the removal and replacement of firebrick, still further improvements in electric furnace installation have continued to be sought.